Topics / From Laboratory to Road

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The Lab to Road project, begun in 2012, documents the widening gap between official vehicle CO2 emissions and real-world CO2 emissions in Europe. As the papers in this series have shown, that gap grew from about 9% in 2001 to well over 40% in 2015. The series also identifies a number of reasons for the increasing gap, including flexibilities in the type-approval procedure that allow for unrealistically low driving resistances and unrepresentative conditions during laboratory testing; fuel-saving technologies such as stop/start systems and hybrid powertrains that prove more effective at reducing CO2 emissions during laboratory testing than during real-world driving; and failure to take into consideration auxiliary devices such as air conditioning and entertainment systems in the type-approval process.

This multi-year project shows the urgent need for improved test procedures. The Worldwide Harmonized Light Vehicle Test Procedure (WLTP) will help but cannot close the gap alone. On-road tests, similar to the Real Driving Emissions (RDE) test procedure for air pollutants, and in-use conformity tests of randomly selected production vehicles should also be introduced.

Most Recent

This update adds one new data source, for a total of 14, covering 16 years, eight countries, and approximately 1.1 million cars. The analysis shows that, in the EU, the gap between official and real-world CO2 emission values continues to grow—from 9% in 2001 to 42% in 2016.

Investigates the gap between real-world and official CO2 emission values in the four largest vehicle markets in the world: China, the EU, Japan, and the United States. The analysis shows that the gap has increased in all markets since 2001.

This update adds two new data sources, for a total of 13, covering 15 years, six countries, and approximately 1 million cars. The analysis shows that, in the EU, the gap between official and real-world CO2 emission values continues to grow—from 9% in 2001 to 42% in 2015.

This update adds one new data source, for a total of 14, covering 16 years, eight countries, and approximately 1.1 million cars. The analysis shows that, in the EU, the gap between official and real-world CO2 emission values continues to grow—from 9% in 2001 to 42% in 2016.

Investigates the gap between real-world and official CO2 emission values in the four largest vehicle markets in the world: China, the EU, Japan, and the United States. The analysis shows that the gap has increased in all markets since 2001.

This update adds two new data sources, for a total of 13, covering 15 years, six countries, and approximately 1 million cars. The analysis shows that, in the EU, the gap between official and real-world CO2 emission values continues to grow—from 9% in 2001 to 42% in 2015.

This annual update to the L2R series analyzes eleven data sources covering fourteen years, six countries, and almost 600,000 vehicles. In the EU the gap between official and real-world vehicle CO2 emissions grew to 38 percent in 2014.

Comparison of official and "real-world" fuel consumption and CO2 emission values for passenger cars in Europe and the United States, which shows that the average discrepancy between them rose from less than 10% in 2001 to 25% in 2011.